Telephone calls are sometimes forwarded from one telephone to another. Consider FIG. 1, which depicts user 110 and user 115 in an office with respective wireline telephones 120 and 125. When user 110 leaves his or her office to work in a computer laboratory, for example, user 110 might forward his or her telephone to a telephone in the computer laboratory. User 110 thus specifies ahead-of-time that any future call directed to telephone 120 should be redirected to the telephone in the computer laboratory (i.e., a call directed to telephone 120 will cause the computer laboratory telephone to “ring,” while telephone 120 will not ring).
As another example, when user 110 receives a call on telephone 120, he or she might wish to transfer the call to another telephone (e.g., a secretary's telephone, etc.) while the call is in progress. Alternatively, user 110 might wish to include another party (e.g., user 115, etc.) in the conversation by bridging the call to an appropriate telephone (e.g., telephone 125, etc.); this is also known as conference calling.
Forwarding is also commonly employed for email. In particular, a forwarding mechanism is established (e.g., creating a forward file in a UNIX-based system, etc.) so that future email messages addressed to a first address are automatically forwarded to a second address.